Prime Minister Prayuth Chan-ocha has said the incident was the worst ever attack on Thailand.

In a separate attack on Tuesday, an explosive device was thrown at a pier in Bangkok. No-one was hurt, but the authorities have not ruled out a link between the incidents.

National police spokesperson Prawut Thawornsiri said on Wednesday that police were also looking for accomplices of the main suspect.

"These types of attacks are not usually planned by one person alone," he said, according to Reuters news agency.

The shrine reopened at about 8am local time (1pm NZST), with a handful of people arriving to place flowers or light incense in front of the slightly damaged statue of the Hindu god Brahma.

A BBC reporter at the scene said there appeared to be low security in place, with the public free to walk in unchecked. She said the last human remains were only cleared from the site earlier on Wednesday.

- BBC

Monks make offerings at the reopened Erawan Shrine on 19 August 2015. Photo: AFP

Photo: AFP

Soldiers at the scene after a bomb exploded outside a religious shrine in central Bangkok. Photo: AFP